Pointing devices for entering commands into a computer are well known in the art. Some pointing devices include a rotatable ball and one or more depressible keys, sometimes referred to as buttons. Electronic encoders sense rotation of the ball, and generate a signal indicative of the ball's rotation to control movement of a cursor on a screen of the computer. Depressing one of the keys permits a user to enter various commands into the computer, based on the location of the cursor. For example, depressing the key may highlight text in a word processing program, pull down a menu, open and close files, and the like.
In a mouse-type pointing device, the rotatable ball extends from a bottom surface of the pointing device, for contacting a work surface, such as a table top. The movement of the pointing device across a work surface causes rotation of the ball and the desired movement of the cursor on the screen.
Many of the currently available pointing devices have disadvantages, however, in that they are uncomfortable or difficult to use, especially for relatively long periods. This may manifest itself in several ways, for example, the hand or arm of a user may feel tired after grasping and operating the pointing device for any length of time.
A need therefore exists for a pointing device that is more comfortable and easy to use, that will minimize any fatigue experienced by a user.